Are urgals good or bad in Eragon?

In the first book they are portrayed as stupid and bloodthirsty creatures, and they are the bulk of Durza's army in the battle of Farthen Dur. However in Eldest the urgals reveal that they were under Durza's spell and thank Eragon for releasing them by killing Durza, and offering their support to the Varden. Throughout books 2 and 3 the reader comes to see the urgals as good rather than bad through Eragon's dialogue with the kull chieftain, Nar Garzhvog.